Smart wear is a new type of product that is designed to apply a new fiber technology for signal transmission to and embed various digital devices in a textile fashion product to utilize the digitalized properties of the digital devices anytime and anywhere. That is, smart wear is a new type of clothing that is manufactured by providing desired digitalized properties to a fiber material or clothing while maintaining the nature of the fiber material or clothing. Accordingly, smart wear is required to transmit digital signals while producing a tactile feeling and physical properties identical to general textiles. In conclusion, smart wear refers collectively to a new concept of clothing that combines high-function material properties (e.g., sensing of external stimuli and self-response to the stimuli) of fibers or clothes with digitalized properties, which are not found in clothes and textiles.
Smart wear has been developed for military applications since the mid-1990's and is currently being developed in various fields, particularly clothing and medical applications. In particular, smart materials based on electronic printing technology can be used to manufacture military textile products for wearable computers. Textile-based electronic circuits can be designed by applying electronic printing technology to smart materials in such a way that conductive fibers or textiles having characteristics and electrical properties of clothing are connected to various electronic components and parts ('interconnection method'). Therefore, electronic printing technology is of great value in the development of smart wear. For example, the application of electronic printing technology to military uniforms offers the possibility to reduce the weight and volume of the military uniforms, thus enabling the development of military uniforms integrated with desired functions, such as injury healing and communication. Soldiers must still carry as much as 45 kg of equipment when fully armed for modern high-tech warfare. Under such circumstances, it is an urgent demand to develop a suitable technology associated with a combination of various factors for a body area network (BAN) to manufacture smart wear.
To meet this demand, various proposals have been made. For example, insulated electric wires, electrically conductive metallic yarns or insulating spun yarns are used to weave textiles. The conductivity of the textiles is determined by the number and size of the metallic yarns or spun yarns.
The problem associated with the attachment of the insulated electric wires to final clothing is that another finishing process must be involved to attach/insulate the insulated electric wires. The additional finishing process requires an increase in production cost. Further, the continuous wearing of the clothing causes disconnection of the insulated electric wires, which makes it difficult to exhibit the inherent functions of the clothing.
PCT International Publication No. WO 2004/107831 suggests a fiber construction comprising one or more conductive fibers and one or more non-conductive fibers cooperating with said one or more conductive fibers to fashion at least one fabric interface wherein said non-conductive fibers provide elasticity to the fiber construction such that said at least one fabric interface is selectively revealed and/or can be accessed coincident with an extension of the fiber construction.
Further, PCT International Publication No. WO 2003/095729 suggests a multilayer woven article having an electronic function woven therein comprising: warp yarn and weft yarn interwoven in a multilayer weave having plural layers defining at least one cavity therebetween; at least one electrically conductive yarn disposed in the warp and/or in the weft and having a portion thereof in one of the plural layers defining the at least one cavity; and a circuit carrier disposed in the cavity and having at least one exposed electrical contact in electrical connection with said at least one electrically conductive yarn.
Meanwhile, fabrics serving as basic materials of smart wear require the following dynamic wearing characteristics. The physical requirements for wearers and devices include placement of the devices, form language of the devices, human movement, human perception of an intimate space, size variation, and attachment of the devices.
Further, in view of the relationship between wearers and ambient atmospheres, containment of the devices, weight of the devices, accessibility, sensory interaction, thermal comfort, aesthetics, long-term effects, etc. are considered [Gemperle, F.; Kasabach, C.; Stivoric, J.; Bauer, M.; Martin, R.; (1998) “Design for Wearability,” Digest of Papers, 2nd International Symposium of Wearable Computer, IEEE Computer Society].
In this connection, it is difficult to design the proposed electrically conductive textiles for smart wear so as to correspond to the placement and form of electronic devices. In other words, no alternative can be provided in view of the physical requirements for wearers and devices. Further, the proposed fabrics suffer from great limitations in fiber volume, washing characteristics, etc. from the viewpoint of the maintenance of the inherent nature of the fibers.